On Tue, 25 Jun 2019 09:04:11 +1200, Peter Reutemann quoted:
'... and complete compatibility with earlier
I think they just mean the GPIO. There are other incompatible changes,
like in the external connectors, and you need a new version of Raspbian
to boot it
Also the new, more powerful CPUs put out quite a lot more heat if you
push them hard. This one may actually need some fans.